Laumonite is a mineral that belongs to the group of zeolites, which are characterized by their porous and alumino-silicate framework structures. Its name is derived from the French mineralogist François Pierre Nicolas Gillet de Laumont, who first discovered it in the late 18th century.
Laumonite typically occurs as colorless to white or pale yellow prismatic crystals, which often form in radiating or intersecting groups. It has a distinct glassy to pearly luster on the cleavage surfaces. The mineral can also occur in fibrous, granular, or massive forms.
Chemically, laumonite is composed of hydrated calcium aluminum silicate, with the chemical formula CaAl2Si4O12·4H2O. It has a relatively low hardness, ranging from 3.5 to 4 on the Mohs scale, and it exhibits a brittle tenacity.
In terms of its geological occurrence, laumonite is commonly found in hydrothermal veins and cavities in volcanic rocks, especially in association with minerals like natrolite, stilbite, heulandite, and calcite. It can also be found in metamorphic rocks, formed through the alteration of plagioclase feldspar.
Laumonite is known for its impressive ability to exhibit a phenomenon called "zeolite twinning," wherein two or more crystals interpenetrate each other. This gives rise to characteristic cross-shaped twin formations. Additionally, the mineral is notable for its strong luminescence under ultraviolet light.
Due to its unique crystal structure and physical properties, laumonite has applications in various fields, including as a catalyst in industrial processes, as an ion-exchange material for water softening,
